How serious is the rivalry between the University of Michigan and Ohio State? It's serious enough for the Ohio governor to discourage usage of the letter 'M' on Saturday.

Ohio Governor John Kasich signed a resolution Friday morning urging residents to avoid using the letter "M" on Saturday, when the two universities face off on the football field.

Kasich dubbed the day "Scarlet Letter Saturday" in the resolution signed by him and Lieutenant Governor Mary Taylor. Scarlet and gray are Ohio State's school colors.

"We, John R. Kasich and Mary Taylor, Governor and Lieutenant Governor of the State of Ohio, do hereby recognize Saturday, Nov. 30, 2013, as SCARLET LETTER SATURDAY throughout Ohio and encourage all Ohioans to avoid using the letter 'M' when possible," the resolution states.

Keeping true to the resolution, Kasich and Taylor crossed out every M on the resolution, including the 'M' in Taylor's first name. Each 'M' in the resolution is crossed out and in red ink.

"Whereas, in the only instance in American history when two states went to war with each other, the state beginning with the letter M lost and whereas in 2013, the United States Fish and Wildlife Service suggested adding the wolverine to the threatened species list under the Endagered Species Act," Kasich wrote in the resolution.

Kasich tweeted the resolution out Friday morning, saying: "Having a little fun with THE rivalry. To*orrow, Ohio goes without a letter in the alphabet."

According to the Associated Press, Buckeyes fans on Twitter have been dropping the letter 'M' from their tweets — even from their own names.

The Wolverines, who are 7-4 this season, are set to face off against the undefeated Buckeyes at Michigan Stadium on Saturday.

Kickoff is at noon on Saturday.

Katrease Stafford covers Ypsilanti for The Ann Arbor News. Reach her at KatreaseStafford@mlive.com or 734-623-2548 and follow her on Twitter.